Design of Porous Banana Foam Mat to Resist Moisture Migration Using a 2-D Stochastic Pore Network and Its Textural Property

Abstract

The high porosity of dried banana foam allows it to quickly adsorb moisture from the air during storage, leading to a loss of quality and textural properties. Therefore, the main purpose of this research was to design and study banana foam structure at the pore level to limit moisture migration using a 2-D stochastic pore network. A 2-D network formed by the interconnection of cylindrical pores was used to represent the voids inside the banana foam and the moisture movement inside the individual pore segments during adsorption was described by Fick's law. The pore network was divided into two layers with different banana foam densities and the top surface of the network was exposed to humid air. The upper layer was assigned with pore sizes from the banana foam density of 0.31 g/cm3, having a void area fraction of 0.22, or from a density of 0.21 g/cm3, having a void area fraction of 0.31; the lower layer was assigned specifically with the pore sizes from the banana foam density of 0.26 g/cm3, having a void area fraction of 0.26. The predictions agreed well with the experimental results, with an R2 value above 0.95. The two-layered banana foam mat with high banana foam density (characterized by mostly small pores) on the upper layer could limit the transport of moisture, with a rate relatively lower than that of a single-layered banana foam mat, and also exhibited more crispiness than the single banana foam. However, when the low banana density was in the upper layer, the two-layered sample adsorbed moisture quickly and its texture was less crispy.